.app-container {
  display: grid;
  grid-template-columns: 250px 1fr;
  grid-template-rows: 80px 1fr;
  height: 100vh;
}

.control-bar {
  grid-column: 1 / -1;
  display: flex;
  justify-content: space-between;
  padding: 10px;
  background: #f5f5f5;
}

.library-sidebar {
  overflow-y: auto;
  border-right: 1px solid #ddd;
}

#song-list li {
  padding: 8px;
  cursor: pointer;
}
#song-list li:hover {
  background: #f0f0f0;
}

.score-panel {
  padding: 20px;
  font-size: 1.2em;
  line-height: 2;
}

.shupu-symbol {
  cursor: pointer;
  transition: all 0.2s;
}
.shupu-symbol:hover {
  transform: scale(1.2);
}
.shupu-symbol.active {
  background: #fff9c4;
  box-shadow: 0 0 5px rgba(0,0,0,0.2);
}